US4218878A - Acceleration monitoring system for protecting gas turbine against damaging operation at resonant speeds - Google Patents
Acceleration monitoring system for protecting gas turbine against damaging operation at resonant speeds Download PDFInfo
- Publication number
- US4218878A US4218878A US05/900,946 US90094678A US4218878A US 4218878 A US4218878 A US 4218878A US 90094678 A US90094678 A US 90094678A US 4218878 A US4218878 A US 4218878A
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- United States
- Prior art keywords
- turbine
- speed
- generating
- rated
- actual
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Links
- 230000001133 acceleration Effects 0.000 title claims description 9
- 238000012544 monitoring process Methods 0.000 title claims description 5
- 239000000446 fuel Substances 0.000 abstract description 4
- 239000003990 capacitor Substances 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000010926 purge Methods 0.000 description 1
- 230000001360 synchronised effect Effects 0.000 description 1
Images
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02C—GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS
- F02C7/00—Features, components parts, details or accessories, not provided for in, or of interest apart form groups F02C1/00 - F02C6/00; Air intakes for jet-propulsion plants
- F02C7/26—Starting; Ignition
Definitions
- the present invention relates to gas turbine controls and more particularly to gas turbine startup speed monitors.
- the present invention is directed to achieving better turbine protection against resonant operation during startup.
- Means are provided for generating an actual turbine speed signal and a reference speed signal which increases over time in accordance with the desired turbine startup speed profile. The two signals are compared and an alarm signal is generated if the difference reaches a first level and a turbine trip signal is generated if the difference reaches a second higher level.
- FIG. 1 shows a block diagram of a turbine acceleration monitor system arranged in accordance with the principles of the invention.
- FIG. 2 shows a desired turbine startup speed profile and a typical actual startup speed profile in which no alarm or trip is generated because actual speed is close enough to desired speed over the whole range.
- FIG. 1 an acceleration monitoring system 10 for a gas turbine 12.
- a fuel control 14 operates a throttle valve 15 in accordance with a stored fuel schedule which normally causes the turbine 12 to be energized such that it moves from ignition to synchronous speed in accordance with a desired speed profile. If the turbine 12 is slowed in its startup, as by override operation of a temperature limit control 16 or a surge limit control 18, the acceleration monitoring system 10 provides turbine protection by alarm and turbine trip actions under preset conditions.
- Logic permissives must first exist before acceleration monitor protection becomes operational. Thus, in this case, a master sequence forcing relay 4X must first be on the turbine 12 must not be in the process of purging which occurs during multiple ignition attempts. In addition, turbine speed must be less than 98% rated. When the logic permissives are satisfied, AND block 22 generates an enabling signal for ramp control logic blocks 24, 26 and 28.
- the actual turbine speed is indicated by a signal from a speed sensor 20. If the turbine speed is less than 63% rated speed, AND gate 24 operates switch 25. Similarly, AND gate 26 operates switch 27 when the turbine speed is between 63% and 90% rated and AND gate 28 operates switch 29 when the turbine speed is between 90% and 98% rated.
- an amplifier 30 is connected as an integrator having a time constant determined by C 1 , R 1 , R 2 and R 3 .
- the circuit is arranged to generate a speed versus time profile having three straight-line segments 25A, 27A and 29A which approximate the desired startup speed profile.
- the absolute value of the difference between the speed reference and actual speed is calculated in block 32 and compared with individual alarm and trip setpoints in comparators 34 and 36.
- AND gates 38 and 40 prevent alarms and trips when master relay 4X is not operated or when actual speed is greater than 98% rated.
- Switch 62 resets the integrator and thus the speed reference to zero when master relay 4X drops out.
- Switch 44 is closed when a fast start is required which increases the rate of all speed references.
- the output from the amplifier represents the speed reference per ramps 27A and 29A, respectively, and the difference between the actual and reference speeds is compared to the alarm and trip setpoints.
- the turbine accelerates along a speed profile such as the profile 46 in FIG. 2. If at any time the actual turbine speed drops to alarm profile 48, an alarm is generated. If the turbine speed drops to trip profile 50, the turbine 12 is tripped.
- One main advantage of the described system is that it provides continuous monitoring of the startup acceleration profile without the use of multiple sequence timers. Further, acceleration is monitored with equal resolution at any discrete speed providing better accuracy than discrete sequence timers.
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Control Of Turbines (AREA)
- Control Of Velocity Or Acceleration (AREA)
Abstract
A fuel control schedules fuel to a gas turbine to produce a scheduled speed profile during startup. The scheduled speed profile is continuously compared to actual turbine speed during startup, and the difference is compared to an alarm setpoint and a trip setpoint. Normally, temperature and surge limit controls prevent the turbine from accelerating too fast; and, if the turbine is accelerating too slowly, an alarm output is generated when the actual/desired speed difference reaches the alarm setpoint and the turbine is tripped when the actual/desired speed difference reaches the trip setpoint.
Description
The present invention relates to gas turbine controls and more particularly to gas turbine startup speed monitors.
In the operation of a power plant gas turbine, there are certain relatively narrow critical speed ranges where resonant conditions occur and costly stress damage or failure of blades and other parts can occur if the turbine is operated at those speeds for even relatively brief periods of time. Although turbine startup normally calls for smooth and continuous increasing speed from ignition to synchronism, the turbine may develop some problem or other circumstances may arise which cause the turbine temperature limit or surge control to hold the turbine at a particular speed for some time.
Protection has conventionally been provided against turbine operation at resonant speeds by the use of a plurality of sequence timers which cause the turbine to trip if the turbine fails to reach a designated higher speed from a designated lower speed within a preset time period measured by the timer associated with that part of the startup sequence. One difficulty with the sequence-timer approach is that the turbine may reach and operate at a critical speed during most of the measured time period, thereby creating the possibility that significant stress damage or part failure will occur before the turbine is signalled to trip by the timer.
The present invention is directed to achieving better turbine protection against resonant operation during startup. Means are provided for generating an actual turbine speed signal and a reference speed signal which increases over time in accordance with the desired turbine startup speed profile. The two signals are compared and an alarm signal is generated if the difference reaches a first level and a turbine trip signal is generated if the difference reaches a second higher level.
FIG. 1 shows a block diagram of a turbine acceleration monitor system arranged in accordance with the principles of the invention.
FIG. 2 shows a desired turbine startup speed profile and a typical actual startup speed profile in which no alarm or trip is generated because actual speed is close enough to desired speed over the whole range.
More particularly, there is shown in FIG. 1 an acceleration monitoring system 10 for a gas turbine 12. A fuel control 14 operates a throttle valve 15 in accordance with a stored fuel schedule which normally causes the turbine 12 to be energized such that it moves from ignition to synchronous speed in accordance with a desired speed profile. If the turbine 12 is slowed in its startup, as by override operation of a temperature limit control 16 or a surge limit control 18, the acceleration monitoring system 10 provides turbine protection by alarm and turbine trip actions under preset conditions.
Logic permissives must first exist before acceleration monitor protection becomes operational. Thus, in this case, a master sequence forcing relay 4X must first be on the turbine 12 must not be in the process of purging which occurs during multiple ignition attempts. In addition, turbine speed must be less than 98% rated. When the logic permissives are satisfied, AND block 22 generates an enabling signal for ramp control logic blocks 24, 26 and 28.
The actual turbine speed is indicated by a signal from a speed sensor 20. If the turbine speed is less than 63% rated speed, AND gate 24 operates switch 25. Similarly, AND gate 26 operates switch 27 when the turbine speed is between 63% and 90% rated and AND gate 28 operates switch 29 when the turbine speed is between 90% and 98% rated.
Generally, an amplifier 30 is connected as an integrator having a time constant determined by C1, R1, R2 and R3. In this instance, as shown in FIG. 2, the circuit is arranged to generate a speed versus time profile having three straight- line segments 25A, 27A and 29A which approximate the desired startup speed profile.
The turbine mechanical designers normally specify the desired turbine startup speed profile which will provide long turbine life. As already indicated, one problem has been that although existing turbine controls have generally provided for startup acceleration, they have not provided adequate protection against a turbine hold at a resonant speed.
During the first speed range, current flows through resistor R1 to the integrating capacitor C1 in proportion to the supply voltage and the value of R1. The output speed reference rises per ramp 25A.
The absolute value of the difference between the speed reference and actual speed is calculated in block 32 and compared with individual alarm and trip setpoints in comparators 34 and 36. AND gates 38 and 40 prevent alarms and trips when master relay 4X is not operated or when actual speed is greater than 98% rated. Switch 62 resets the integrator and thus the speed reference to zero when master relay 4X drops out. Switch 44 is closed when a fast start is required which increases the rate of all speed references.
Similarly, during the second and third speed ramps, the output from the amplifier represents the speed reference per ramps 27A and 29A, respectively, and the difference between the actual and reference speeds is compared to the alarm and trip setpoints. Normally, the turbine accelerates along a speed profile such as the profile 46 in FIG. 2. If at any time the actual turbine speed drops to alarm profile 48, an alarm is generated. If the turbine speed drops to trip profile 50, the turbine 12 is tripped.
One main advantage of the described system is that it provides continuous monitoring of the startup acceleration profile without the use of multiple sequence timers. Further, acceleration is monitored with equal resolution at any discrete speed providing better accuracy than discrete sequence timers.
Claims (3)
1. An improved acceleration monitoring system for protecting a gas turbine against resonant speed operation, said system comprising means for generating a signal representative of actual turbine speed, means for generating a reference signal which substantially represents desired turbine startup speed as a continuous function of time, means for continuously comparing the actual and reference speed signals and for generating an output representing the difference, means for generating an alarm signal when the difference output reaches a first value which indicates the pssibility of an undesired hold at a resonant speed, and means for generating a turbine trip signal when the difference output reaches a predetermined second value higher than the first value.
2. A system as set forth in claim 1 wherein said reference signal generating means includes first means for generating a first ramp signal having a first slope over a first turbine speed range, second means for generating a second ramp signal having a second slope less than the first slope over a second turbine speed range, and third means for generating a third ramp signal having a third slope less than the second slope over a third turbine speed range.
3. A system as set forth in claim 2 wherein the first speed range is from 0% rated to about 60% rated, the second speed range is from about 60% rated to about 90% rated and the third speed range is from about 90% rated to about 98% rated.
Priority Applications (8)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US05/900,946 US4218878A (en) | 1978-04-28 | 1978-04-28 | Acceleration monitoring system for protecting gas turbine against damaging operation at resonant speeds |
CA315,558A CA1110739A (en) | 1978-04-28 | 1978-10-31 | Acceleration monitoring system for protecting gas turbine against demaging operation at resonant speeds |
GB7913131A GB2020814B (en) | 1978-04-28 | 1979-04-12 | Monitoring turbine speed |
BR7902432A BR7902432A (en) | 1978-04-28 | 1979-04-20 | ACCELERATION MONITORING SYSTEM TO PROTECT A TURBINE AGAINST RESONANT SPEED OPERATION |
JP54049185A JPS581251B2 (en) | 1978-04-28 | 1979-04-23 | Turbine acceleration monitoring device |
IT22041/79A IT1112783B (en) | 1978-04-28 | 1979-04-23 | ACCELERATION CONTROL SYSTEM TO PROTECT THE GAS TURBINE FROM HARMFUL OPERATION AT RESONANT SPEED |
AR276289A AR221088A1 (en) | 1978-04-28 | 1979-04-24 | MONITORING ACCELERATION PROVISION TO PROTECT GAS TURBINES FROM INJURIOUS OPERATION AT RESONANCE SPEEDS |
BE0/194893A BE875924A (en) | 1978-04-28 | 1979-04-27 | ACCELERATION CONTROL SYSTEM TO PROTECT A GAS TURBINE AGAINST OPERATION AT RESONANCE SPEEDS |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US05/900,946 US4218878A (en) | 1978-04-28 | 1978-04-28 | Acceleration monitoring system for protecting gas turbine against damaging operation at resonant speeds |
Publications (1)
Publication Number | Publication Date |
---|---|
US4218878A true US4218878A (en) | 1980-08-26 |
Family
ID=25413341
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US05/900,946 Expired - Lifetime US4218878A (en) | 1978-04-28 | 1978-04-28 | Acceleration monitoring system for protecting gas turbine against damaging operation at resonant speeds |
Country Status (8)
Country | Link |
---|---|
US (1) | US4218878A (en) |
JP (1) | JPS581251B2 (en) |
AR (1) | AR221088A1 (en) |
BE (1) | BE875924A (en) |
BR (1) | BR7902432A (en) |
CA (1) | CA1110739A (en) |
GB (1) | GB2020814B (en) |
IT (1) | IT1112783B (en) |
Cited By (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4337615A (en) * | 1979-03-21 | 1982-07-06 | The Garrett Corporation | Gas turbine fuel control system |
US4619110A (en) * | 1983-07-13 | 1986-10-28 | Moore M Samuel | Helicopter engine warning or control system |
US4817046A (en) * | 1986-04-10 | 1989-03-28 | United Technologies Corporation | Detection of engine failure in a multi-engine aircraft |
US5129221A (en) * | 1989-05-23 | 1992-07-14 | Rolls-Royce Plc | Gas turbine engine fuel control system with enhanced relight capability |
US20040128035A1 (en) * | 2002-12-30 | 2004-07-01 | Vandervort Christian L. | System and method for steam turbine backpressure control using dynamic pressure sensors |
US20060129301A1 (en) * | 2004-12-14 | 2006-06-15 | General Electric Company | Method and apparatus for assessing gas turbine acceleration capability |
CN103452605A (en) * | 2013-09-02 | 2013-12-18 | 哈尔滨热电有限责任公司 | Backpressure protection control method based on DCS (Distributed control system) system |
CN103485835A (en) * | 2013-10-30 | 2014-01-01 | 哈尔滨热电有限责任公司 | Backpressure protection control method for 300MW high back pressure unit system |
CN103485838A (en) * | 2013-09-03 | 2014-01-01 | 哈尔滨热电有限责任公司 | Protection safety margin and back pressure protection control method used during change of heating steam extraction capacity of 300MW high back pressure unit |
CN105888743A (en) * | 2016-04-12 | 2016-08-24 | 国网上海市电力公司 | Supercritical unit DEH side primary frequency modulation method |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US8818683B2 (en) | 2006-04-21 | 2014-08-26 | General Electric Company | Method and apparatus for operating a gas turbine engine |
Citations (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3382671A (en) * | 1965-12-16 | 1968-05-14 | Beta Corp | Control for gas turbine emergency power system |
US3469395A (en) * | 1965-10-22 | 1969-09-30 | Holley Carburetor Co | Gas turbine engine digital fuel control |
US3520133A (en) * | 1968-03-14 | 1970-07-14 | Gen Electric | Gas turbine control system |
US3620010A (en) * | 1970-02-02 | 1971-11-16 | Gen Electric | Gas turbine speed-load control |
US3630023A (en) * | 1968-10-24 | 1971-12-28 | Honeywell Inc | Fluidic engine control apparatus |
US3662545A (en) * | 1970-08-24 | 1972-05-16 | Gen Electric | Acceleration control circuit for a gas turbine |
US3911285A (en) * | 1973-06-20 | 1975-10-07 | Westinghouse Electric Corp | Gas turbine power plant control apparatus having a multiple backup control system |
US4010605A (en) * | 1974-08-08 | 1977-03-08 | Westinghouse Electric Corporation | Accurate, stable and highly responsive gas turbine startup speed control with fixed time acceleration especially useful in combined cycle electric power plants |
US4122667A (en) * | 1975-12-08 | 1978-10-31 | Nissan Motor Company, Limited | System for detecting abnormality in fuel feed control system of gas turbine engine |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5838782B2 (en) * | 1975-08-01 | 1983-08-25 | ミノルタ株式会社 | Denshishashin Fukushiyaki |
JPS5848600B2 (en) * | 1975-09-08 | 1983-10-29 | バブコツク日立株式会社 | Cement clinker |
-
1978
- 1978-04-28 US US05/900,946 patent/US4218878A/en not_active Expired - Lifetime
- 1978-10-31 CA CA315,558A patent/CA1110739A/en not_active Expired
-
1979
- 1979-04-12 GB GB7913131A patent/GB2020814B/en not_active Expired
- 1979-04-20 BR BR7902432A patent/BR7902432A/en unknown
- 1979-04-23 JP JP54049185A patent/JPS581251B2/en not_active Expired
- 1979-04-23 IT IT22041/79A patent/IT1112783B/en active
- 1979-04-24 AR AR276289A patent/AR221088A1/en active
- 1979-04-27 BE BE0/194893A patent/BE875924A/en not_active IP Right Cessation
Patent Citations (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3469395A (en) * | 1965-10-22 | 1969-09-30 | Holley Carburetor Co | Gas turbine engine digital fuel control |
US3382671A (en) * | 1965-12-16 | 1968-05-14 | Beta Corp | Control for gas turbine emergency power system |
US3520133A (en) * | 1968-03-14 | 1970-07-14 | Gen Electric | Gas turbine control system |
US3630023A (en) * | 1968-10-24 | 1971-12-28 | Honeywell Inc | Fluidic engine control apparatus |
US3620010A (en) * | 1970-02-02 | 1971-11-16 | Gen Electric | Gas turbine speed-load control |
US3662545A (en) * | 1970-08-24 | 1972-05-16 | Gen Electric | Acceleration control circuit for a gas turbine |
US3911285A (en) * | 1973-06-20 | 1975-10-07 | Westinghouse Electric Corp | Gas turbine power plant control apparatus having a multiple backup control system |
US4010605A (en) * | 1974-08-08 | 1977-03-08 | Westinghouse Electric Corporation | Accurate, stable and highly responsive gas turbine startup speed control with fixed time acceleration especially useful in combined cycle electric power plants |
US4122667A (en) * | 1975-12-08 | 1978-10-31 | Nissan Motor Company, Limited | System for detecting abnormality in fuel feed control system of gas turbine engine |
Cited By (13)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4337615A (en) * | 1979-03-21 | 1982-07-06 | The Garrett Corporation | Gas turbine fuel control system |
US4619110A (en) * | 1983-07-13 | 1986-10-28 | Moore M Samuel | Helicopter engine warning or control system |
US4817046A (en) * | 1986-04-10 | 1989-03-28 | United Technologies Corporation | Detection of engine failure in a multi-engine aircraft |
US5129221A (en) * | 1989-05-23 | 1992-07-14 | Rolls-Royce Plc | Gas turbine engine fuel control system with enhanced relight capability |
DE10361755B4 (en) * | 2002-12-30 | 2010-12-16 | General Electric Co. | Backpressure monitoring system and method for steam turbines using dynamic pressure sensors |
US20040128035A1 (en) * | 2002-12-30 | 2004-07-01 | Vandervort Christian L. | System and method for steam turbine backpressure control using dynamic pressure sensors |
US6865935B2 (en) * | 2002-12-30 | 2005-03-15 | General Electric Company | System and method for steam turbine backpressure control using dynamic pressure sensors |
CN1329721C (en) * | 2002-12-30 | 2007-08-01 | 通用电气公司 | System and method for steam turbine backpressure control using dynamic pressure sensors |
US20060129301A1 (en) * | 2004-12-14 | 2006-06-15 | General Electric Company | Method and apparatus for assessing gas turbine acceleration capability |
CN103452605A (en) * | 2013-09-02 | 2013-12-18 | 哈尔滨热电有限责任公司 | Backpressure protection control method based on DCS (Distributed control system) system |
CN103485838A (en) * | 2013-09-03 | 2014-01-01 | 哈尔滨热电有限责任公司 | Protection safety margin and back pressure protection control method used during change of heating steam extraction capacity of 300MW high back pressure unit |
CN103485835A (en) * | 2013-10-30 | 2014-01-01 | 哈尔滨热电有限责任公司 | Backpressure protection control method for 300MW high back pressure unit system |
CN105888743A (en) * | 2016-04-12 | 2016-08-24 | 国网上海市电力公司 | Supercritical unit DEH side primary frequency modulation method |
Also Published As
Publication number | Publication date |
---|---|
CA1110739A (en) | 1981-10-13 |
IT1112783B (en) | 1986-01-20 |
GB2020814B (en) | 1982-08-25 |
JPS581251B2 (en) | 1983-01-10 |
JPS54145810A (en) | 1979-11-14 |
BR7902432A (en) | 1979-10-23 |
AR221088A1 (en) | 1980-12-30 |
IT7922041A0 (en) | 1979-04-23 |
GB2020814A (en) | 1979-11-21 |
BE875924A (en) | 1979-10-29 |
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